Median effective target plasma concentration of propofol inhibiting response to laryngeal mask airway insertion when combined with dexmedetomidine / 中华麻醉学杂志

Objective To determine the median effective target plasma concentration (EC50) of propofol inhibiting the response to laryngeal mask airway (LMA) insertion when combined with dexmedetomidine.Methods ASA Ⅰ or Ⅱ patients of both sexes,aged 20-60 yr,with body mass index 20-25 kg/m2,scheduled for surgeries under general anesthesia,were studied.EC50 of propofol was determined by modified Dixon' s up-and-down sequential experiment.After dexmedetomidine 1.0 μg/kg was infused over 10 min,propofol was infused by targetcontrolled infusion.The initial target plasma concentration of propofol was set at 3.0 μg/ml.LMA was inserted when the target effect-site concentration of propofol and target plasma concentration of propofol reached the balance and BIS value was 50-60.Each time the target concentration increased/decreased by 0.2 μg/ml according to the occurrence of the response to LMA insertion.The response to LMA insertion was defined as the occurrence of coughing,body movement,laryngospasm or systemic voluntary movement.EC50 and 95 ％ confidence interval (CI)of propofol for inhibition of the response to LMA insertion were calculated.Results The EC50 of propofol required for inhibition of the response to LMA insertion was 2.351 (95％ Cl 1.737-2.600) μg/ml when combined with dexmedetomidine 1.0 μg/kg.Conclusion The EC50 of propofol inhibiting the response to LMA insertion is 2.351 μg/ml when combined with dexmedetomidine.

Experimental study on mechanical and biomechanical reconstruction of bone defect of long bone near joint / 中国组织工程研究

BACKGROUND:The repairing of bone defect near joint in long bone resulting from complicated comminuted fracture or excision of bone tumor is very difficult. It is a much studied issue to find a feasible solution to this problem.OBJECTIVE: To explore a feasible treatment to bone defect near joint in long bone through comparative observation of 3 reconstruction methods.DESIGN: A completely randomized experiment with self-control and mutual control.SETTING: Laboratory for Experimental Animals, First Hospital of Jilin University.MATERIALS: Twelve healthy adult hybrid dogs, 5 males and 7 females weighing 12 to 18 kg, were recruited.METHODS: The bone defects near joints were established in upper femoral condyle in the 12 dogs, which were reconstructed by 3 operation styles: only filling with bone cement, filling with bone cement + autogenous ilium bone graft, and filling with bone cement + autogenous ilium bone graft + fixation with L-trapezoid compression plate. There was one dog in each method. The specimens were harvested at the end of weeks 3, 6, 12and 24, respectively, after operation. One week before specimens were harvested the fluorescent labeling was prepared; we conducted vascular perfusion of disulphine blue before the animals were executed.MAIN OUTCOME MEASURES: A series of examinations were carried out, including X-ray film, biomechanical test, intravascular perfusion and tetracycline fluorescent labeling. The bone healing, blood supply recovery and biomechanics were observed in the three groups.RESULTS: The 12 dogs all entered the result analysis. ① Results of Xray examination: Two cases of fracture occurred in experimental side at 6and 12 weeks in group Ⅰ; one case of fracture occurred in experimental side at 6 weeks in group Ⅱ. No fracture happened in group Ⅲ. ② Bone stiffness assayed with biomechanics: It decreased in experimental side as compared to control side by 67% and 70% in group Ⅰ; 66%, 76% and 46% in group Ⅱ; and 8% in group Ⅲ. ③ Specimen observation after operation: Bone formation, callus, and blood supply recovery were significantly better in group Ⅲ than in groups Ⅰ and Ⅱ at all stages.CONCLUSION: The third operation, filling with bone cement + autogenous ilium bone graft + fixation with L-trapezoid compression plate, is an ideal method of bone reconstruction. It can recover bone function, and prevent complications such as refracture and bone nonunion.

Changes of cerebralspinal fluid and intracranial pressure of the in the patients with intracranial tumor during nurosurgery / 中华麻醉学杂志

Objective To investigate the changes of pH of cerebralspinal fluid (CSFpH) and intracranial pressure(ICP) in the brain tumor patients during nurosurgery, in order to explore the measures for regulating ICP during these procedures Methods Forty-five patients suffering from brain tumor, scheduled for nurosurgery under diazepam-fentanyl-sodium thiopental-atracurium anesthesia, were randomly selected CSFpH and ICP were measured concomitantly during different phases of operation, including pre-anesthetic,post-anethetic periods, tracheal intubation, incision of the durae, excision of tumor and extubationResults As compared with those before anesthesia ,ICP increased gradually and CSFpH decreased gradually after the induction of anesthesia (P